TORONTO — Researchers have grown a rat lung in the lab, taking a preliminary step in the quest to regenerate the vital organs for humans. It's not the first time an animal organ has been virtually grown from scratch -- another research team grew a beating rat heart two years ago using a similar method -- but regenerating the structurally complex breathing organ is considered no easy feat.
Yet the need for lung transplants is great, with more than 400,000 North Americans dying each year from lung disease and the supply of donor organs falling far short of demand. Even with a transplant, only about 10 to 20 per cent of recipients survive 10 years.
That's one of the reasons behind the push to one day have the know-how to regenerate human lungs, agreed Thomas Petersen, a member of a Yale University research team that grew the animal lung in the lab.
The researchers took a rat lung, washed away its interior cells and DNA with a mix of chemicals that left only the organ's outer shell, or matrix, the branching airway structures and the blood vessel system.
"It took a bit of work to get something that would take away the cells but not the matrix," Petersen, postdoctoral associate in biomedical engineering, said from New Haven, Conn.
The team then seeded the organ's shell, which acts as a scaffolding, with a combination of lung-specific cells cultured from adult and baby rats. It was then placed in a bioreactor designed to mimic some aspects of the fetal lung environment.
After a week in the bioreactor, the cells repopulated the decellularized matrix with functional lung cells -- in effect, producing a whole new lung.
When implanted into rats for short intervals -- from 45 minutes to two hours -- the engineered lungs pinked up as blood flowed in and out of the organ.
"We succeeded in engineering an implantable lung in our rat model that could efficiently exchange oxygen and carbon dioxide, and could oxygenate hemoglobin in the blood," said principal investigator Dr. Laura Niklason, vice-chair of anesthesiology and biomedical engineering at Yale.
"This is an early step in the regeneration of entire lungs for larger animals and, eventually, for humans," said Niklason, whose team's paper is published online this week in Science Express.
Petersen conceded that when the scientists witnessed the flow of blood through the lung they had grown, they experienced a bit of a eureka moment.
"It was quite exciting. We really had no idea if it would work at all," he said. "You can actually see the blood turn from a dark red to a bright red ... dark going in, bright going out."
Still, Petersen said there are many hurdles to overcome and years of research are needed in rats and other animals before they would even attempt growing a human lung, which would likely be generated using cells derived from a patient's own stem cells.
"So there is a lot more that we need to do. But by showing that this approach can work.
anybody need a lung??
Yet the need for lung transplants is great, with more than 400,000 North Americans dying each year from lung disease and the supply of donor organs falling far short of demand. Even with a transplant, only about 10 to 20 per cent of recipients survive 10 years.
That's one of the reasons behind the push to one day have the know-how to regenerate human lungs, agreed Thomas Petersen, a member of a Yale University research team that grew the animal lung in the lab.
The researchers took a rat lung, washed away its interior cells and DNA with a mix of chemicals that left only the organ's outer shell, or matrix, the branching airway structures and the blood vessel system.
"It took a bit of work to get something that would take away the cells but not the matrix," Petersen, postdoctoral associate in biomedical engineering, said from New Haven, Conn.
The team then seeded the organ's shell, which acts as a scaffolding, with a combination of lung-specific cells cultured from adult and baby rats. It was then placed in a bioreactor designed to mimic some aspects of the fetal lung environment.
After a week in the bioreactor, the cells repopulated the decellularized matrix with functional lung cells -- in effect, producing a whole new lung.
When implanted into rats for short intervals -- from 45 minutes to two hours -- the engineered lungs pinked up as blood flowed in and out of the organ.
"We succeeded in engineering an implantable lung in our rat model that could efficiently exchange oxygen and carbon dioxide, and could oxygenate hemoglobin in the blood," said principal investigator Dr. Laura Niklason, vice-chair of anesthesiology and biomedical engineering at Yale.
"This is an early step in the regeneration of entire lungs for larger animals and, eventually, for humans," said Niklason, whose team's paper is published online this week in Science Express.
Petersen conceded that when the scientists witnessed the flow of blood through the lung they had grown, they experienced a bit of a eureka moment.
"It was quite exciting. We really had no idea if it would work at all," he said. "You can actually see the blood turn from a dark red to a bright red ... dark going in, bright going out."
Still, Petersen said there are many hurdles to overcome and years of research are needed in rats and other animals before they would even attempt growing a human lung, which would likely be generated using cells derived from a patient's own stem cells.
"So there is a lot more that we need to do. But by showing that this approach can work.
anybody need a lung??
....if you can believe it, who knows what the mind can do, maybe keep us alive forever in the physical, never know with a little "organ maker" in the mix.....mo
